Hybrid Residential Ground-Coupled Heat Pump

ABSTRACT

Systems and methods are disclosed that include providing a hybrid heat pump system with a heat pump connected in fluid communication with an outdoor unit and a ground heat exchanger via a plurality of valves. The hybrid heat pump system also includes a system controller that selectively configures the plurality of valves to alter a fluid flow path through at least one of the outdoor unit that exchanges heat between a fluid carried by an outdoor heat exchanger of the outdoor unit and ambient outdoor air and the ground heat exchanger that exchanges heat between the fluid carried by the ground heat exchanger and the ground in order to maximize heat transfer efficiency between the fluid and the ambient outdoor air and/or the ground based on various temperatures measured by the hybrid heat pump system.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 62/424,160 filed Nov. 18, 2016 by Roy Crawford entitled “Hybrid Residential Ground-Coupled Heat Pump,” the disclosure of which is hereby incorporated by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Heat pump systems may generally be used in residential and/or commercial areas for heating and/or cooling to create comfortable temperatures inside those structures. Some heat pump systems may be split-type heating, ventilation, and/or cooling (HVAC) heat pump systems that include an outdoor unit that exchanges heat with ambient air outside of a structure. Alternatively, some heat pump systems may be geothermal heat pump systems that include a heat exchanger that exchanges heat with the ground environment near a structure. Regardless of the type of heat pump system, most heat pump systems attempt to maximize a temperature gradient and/or efficiency of the components of the heat pump system to effectively transfer heat to and/or from a comfort zone in a structure.

SUMMARY

In some embodiments of the disclosure, a hybrid heat pump system is disclosed. The hybrid heat pump system includes a heat pump connected in fluid communication with an outdoor unit and a ground heat exchanger via a plurality of valves. The hybrid heat pump system also includes a system controller that selectively configures the plurality of valves to alter a fluid flow path through at least one of the outdoor unit that exchanges heat between a fluid carried by an outdoor heat exchanger of the outdoor unit and ambient outdoor air and the ground heat exchanger that exchanges heat between the fluid carried by the ground heat exchanger and the ground in order to maximize heat transfer efficiency between the fluid and the ambient outdoor air and/or the ground based on various temperatures measured by the hybrid heat pump system.

In other embodiments of the disclosure, a hybrid heat pump system is provided that includes a heat pump, an outdoor heat exchanger, a ground heat exchanger, and a fluid flow path including a plurality of valves selectively configurable to circulate fluid between the heat pump, the outdoor heat exchanger, and the ground heat exchanger.

In another embodiment, a hybrid heat pump system is provided that includes a heat pump, an outdoor heat exchanger, a ground heat exchanger, and a fluid flow path including a plurality of valves selectively configurable in a first mode to circulate fluid between the heat pump and the ground heat exchanger, in a second mode to circulate fluid between the heat pump and the outdoor heat exchanger, in a third mode to circulate fluid from the heat pump to the outdoor heat exchanger and then circulate the fluid from the outdoor heat exchanger to the ground heat exchanger, and in a fourth mode to circulate fluid from the heat pump to the ground heat exchanger and then circulate the fluid from the ground heat exchanger to enter the outdoor heat exchanger.

In another embodiment, a method of operating a hybrid heat pump system is provided that includes circulating fluid between a heat pump and a ground heat exchanger in a first mode; circulating fluid between the heat pump and an outdoor heat exchanger in a second mode; circulating fluid from the heat pump to the outdoor heat exchanger and then circulating the fluid from the outdoor heat exchanger to the ground heat exchanger in a third mode; and circulating fluid from the heat pump to the ground heat exchanger and then circulating the fluid from the ground heat exchanger to enter the outdoor heat exchanger in a fourth mode.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description:

FIG. 1 is a schematic diagram of a hybrid heat pump system according to an embodiment of the disclosure;

FIG. 2 is a schematic diagram of the hybrid heat pump system of FIG. 1 configured in a first mode of operation according to an embodiment of the disclosure;

FIG. 3 is a schematic diagram of the hybrid heat pump system of FIG. 1 configured in a second mode of operation according to an embodiment of the disclosure;

FIG. 4 is a schematic diagram of the hybrid heat pump system of FIG. 1 configured in a third mode of operation according to an embodiment of the disclosure;

FIG. 5 is a schematic diagram of the hybrid heat pump system of FIG. 1 configured in a fourth mode of operation according to an embodiment of the disclosure; and

FIG. 6 is a flowchart of a method of operating the hybrid heat pump system of FIGS. 1-5 according to an embodiment of the disclosure.

DETAILED DESCRIPTION

Referring now to FIG. 1, a schematic diagram of a hybrid heat pump system 100 is shown according to an embodiment of the disclosure. The hybrid heat pump system 100 comprises a system controller 102, a heat pump 104, an outdoor unit 106 comprising an outdoor fan 122 and an outdoor heat exchanger 124, and a ground heat exchanger 108 comprising a plurality of ground loops 126. The hybrid heat pump system 100 may also comprise a plurality of valves, including a first valve 110, a second valve 112, a third valve 114, a fourth valve 116, a fifth valve 118, and a sixth valve 120 that may be selectively configured and/or controlled by the system controller 102 to connect each of the heat pump 104, the outdoor heat exchanger 124 of the outdoor unit 106, and the ground heat exchanger 108 in fluid communication and/or alter the fluid flow path through each of the outdoor heat exchanger 124 of the outdoor unit 106 and the ground heat exchanger 108. Additionally, in some embodiments, the hybrid heat pump system 100 may comprise multiple outdoor units 106 and/or multiple ground heat exchangers 108.

Most generally, the heat pump 104 may be selectively operated by the system controller 102 to implement one or more substantially closed thermodynamic refrigeration cycles to provide a cooling functionality (hereinafter “cooling mode”) and/or a heating functionality (hereinafter “heating mode”). The heat pump 104 generally comprises a plurality of heat exchangers (condenser, evaporator) to carry out the substantially closed thermodynamic refrigeration cycles by circulating a refrigerant within a structure, such as structure 200, to deliver temperature conditioned air through a plurality of fluid air ducts to a plurality of zones associated with the structure 200. However, in some embodiments, the heat pump 104 may comprise only one of the heat exchangers and be configured to carry out the substantially closed thermodynamic refrigeration cycles in conjunction with a traditional air handling unit.

Additionally, the heat pump 104 may also be configured to selectively circulate a fluid (i.e. water, water/glycol mixture, and/or any other heat transfer medium) through a selectively alterable fluid flow path between the heat pump 104, the outdoor heat exchanger 124 of the outdoor unit 106, and the ground heat exchanger 108. Generally, the fluid flow path may begin at a heat pump outlet 128 of the heat pump 104, pass through at least one of the outdoor heat exchanger 124 of the outdoor unit 106 and the ground heat exchanger 108, and return to a heat pump inlet 130 of the heat pump 104. Further, the heat pump 104 may also comprise a plurality of temperature sensors for measuring the temperature of the fluid circulated by the heat pump 104 at the heat pump outlet 128 and the temperature of the fluid circulated by the heat pump 104 at the heat pump inlet 130. As will be discussed later herein, the system controller 102 may selectively configure and/or control the plurality of valves 110, 112, 114, 116, 118, 120 to alter the fluid flow path between the heat pump outlet 128 and the heat pump inlet 130.

The outdoor unit 104 comprises an outdoor fan 122 and an outdoor heat exchanger 124 having an inlet 132 and outlet 134 whereby the fluid circulated by the heat pump 104 may enter and exit the outdoor unit 106, respectively. However, as will be discussed later, it will be appreciated that fluid flow path through the outdoor heat exchanger 124 may be reversed, such that the fluid circulated by the heat pump 104 may enter via the outlet 134 of the outdoor heat exchanger 124 and exit via the inlet 132 of the outdoor heat exchanger 124. As such, the outdoor unit 106 may, at least in some embodiments, comprise a traditional outdoor unit of a split-type heat pump heating, ventilation, and/or air conditioning (HVAC) system without a traditional compressor and/or expansion device.

The outdoor fan 122 may generally be configured to provide an airflow of ambient outdoor air 201 through the outdoor unit 106 and/or the outdoor heat exchanger 124 to promote heat transfer between the airflow and fluid flowing through the outdoor heat exchanger 124. The outdoor fan 122 may generally be configured as a modulating and/or variable speed fan capable of being operated at a plurality of speeds over a plurality of speed ranges. However, in other embodiments, the outdoor fan 122 may be configured as a single speed fan. The outdoor heat exchanger 124 may generally be configured to promote heat transfer between the airflow generated by the outdoor fan 122 that comes into contact with and/or passes through the outdoor heat exchanger 124 and the fluid circulated through the outdoor heat exchanger 124 such that heat is exchanged between the fluid and the airflow. The outdoor heat exchanger 124 may generally comprise a spine-fin heat exchanger, a plate-fin heat exchanger, a microchannel heat exchanger, or any other suitable type of heat exchanger. Additionally, the outdoor unit 106 may also comprise a plurality of temperature sensors for measuring the temperature of the outdoor heat exchanger 124, the temperature of the fluid circulated by the heat pump 104 at the inlet 132, the temperature of the fluid circulated by the heat pump 104 at the outlet 134, and/or the temperature of the ambient outdoor air 201.

The ground heat exchanger 108 generally comprises a subsurface heat exchanger buried in the ground 202 and configured to exchange heat between the fluid circulated by the heat pump 104 and the ground 202. The ground heat exchanger 108 comprises an inlet 136 whereby the fluid circulated by the heat pump 104 may enter the ground heat exchanger 108, and an outlet 138 whereby the fluid circulated by the heat pump 104 may exit the ground heat exchanger 108. The ground heat exchanger 108 may also comprise a plurality of ground loops 126 connected in parallel between the inlet 136 and the outlet 138. However, in some embodiments, the ground heat exchanger 108 may only comprise one ground loop 126. The ground loops 126 may generally be formed from copper tubing and/or any other material configured to promote heat transfer between the fluid circulated through the ground loops 126 and/or the ground heat exchanger 108 and the ground 202. In some embodiments, the ground loops 126 may comprise straight lengths of tubing having a u-bend at a distal end of each ground loop 126. In other embodiments, the ground loops 126 may each comprise a series of loops adjacently offset from one another. In yet other embodiments, the ground loops 126 may be formed in any shape depending on the available ground 202 space and/or the configuration and/or size of the structure 200. Additionally, the ground heat exchanger 108 may also comprise a plurality of temperature sensors for measuring the temperature of the fluid circulated by the heat pump 104 at the inlet 136, the temperature of the fluid circulated by the heat pump 104 at the outlet 138, and/or the temperature of the ground 202.

The plurality of valves 110, 112, 114, 116, 118, 120 may be selectively configured by the system controller 102 to alter the fluid flow path from a most upstream point in the fluid flow path at the heat pump outlet 128 to a most downstream point in the fluid flow path at the heat pump inlet 130 selectively opening and/or closing the valves 110, 112, 114, 116, 118, 120. However, in alternative embodiments, the plurality of valves 110, 112, 114, 116, 118, 120 may be selectively configured by a heat pump 104 controller and/or an outdoor unit 106 controller. The fifth valve 118 is connected in fluid communication inline between the heat pump outlet 128 and the inlet 136 of the ground heat exchanger 108. The sixth valve 120 is connected in fluid communication inline between the heat pump inlet 130 and the outlet 138 of the ground heat exchanger 108. The first valve 110 is connected in fluid communication between the heat pump inlet 130 at a location downstream from the sixth valve 120 and the inlet 132 of the outdoor heat exchanger 124 of the outdoor unit 106.

The second valve 112 is connected in fluid communication between the heat pump outlet 128 at a location upstream from the fifth valve 118 and the inlet 132 of the outdoor heat exchanger 124 of the outdoor unit 106. Thus, in some embodiments, the first valve 110 and the second valve 112 may be connected in fluid communication in parallel between the heat pump inlet 130 and the heat pump outlet 128, respectively, to the inlet 132 of the outdoor heat exchanger 124 of the outdoor unit 106. The third valve 114 is connected in fluid communication between the outlet 138 of the ground heat exchanger 108 at a location upstream from the sixth valve 120 and the outlet 134 of the outdoor heat exchanger 124 of the outdoor unit 106. The fourth valve 116 is connected in fluid communication between the inlet 136 of the ground heat exchanger 108 at a location downstream from the fifth valve 118 and the outlet 134 of the outdoor heat exchanger 124 of the outdoor unit 106. Thus, in some embodiments, the third valve 114 and the fourth valve 116 may be connected in fluid communication in parallel between the inlet 136 and the outlet 138, respectively, to the outlet 134 of the outdoor heat exchanger 124 of the outdoor unit 106. Accordingly, the fifth valve 118 may be connected in fluid communication between the connections of the second valve 112 and the fourth valve 116 to the heat pump outlet 128 and the inlet 136 of the ground heat exchanger 108, respectively. Additionally, the sixth valve 120 may be connected in fluid communication between the connections of the first valve 110 and the third valve 114 to the heat pump inlet 130 and the outlet 138 of the ground heat exchanger 108, respectively.

The system controller 102 may generally be configured to control the components of the hybrid heat pump system 100, including, but not limited to the heat pump 104, the outdoor unit 106 and its components, and the plurality of valves 110, 112, 114, 116, 118, 120 to selectively circulate a fluid (i.e. water, water/glycol mixture, and/or any other heat transfer medium) through a selectively altered fluid circuit between the heat pump 104, the outdoor heat exchanger 124 of the outdoor unit 106, and the ground heat exchanger 108. The system controller 102 may also be configured to selectively communicate with other controllers, such as a heat pump 104 controller, an outdoor unit 106 controller, and/or other components of the hybrid heat pump system 100. Additionally, the system controller 102 may selectively communicate with and/or control one or more system specific controllers, such as a heat pump 104 controller and/or an outdoor unit 106 controller, to operate the hybrid heat pump system 100 in a heating mode and/or a cooling mode. In some embodiments, the system controller 102 may also provide commands to the heat pump 104 controller and/or the outdoor unit 106 controller to selectively alter the fluid flow path between the heat pump 104, the outdoor heat exchanger 124 of the outdoor unit 106, and the ground heat exchanger 108.

The system controller 102 may generally comprise a temperature sensor configured to monitor the temperature inside the structure 200 and/or may further be configured to control operation of the hybrid heat pump system 100 and/or the heat pump 104 in a heating mode and/or a cooling mode to provide temperature conditioned air through a plurality of fluid air ducts to a plurality of zones associated with the structure 200 in response to the measured temperature inside the structure 200 as compared with a set point temperature. Additionally, the system controller 102 may also be configured to monitor a plurality of temperature sensors associated with different zones of the structure. As such, in some embodiments, the system controller 102 may be configured as a thermostat for controlling the supply of conditioned air to zones associated with the structure 200.

Furthermore, the system controller 102 may also be configured to monitor and/or communicate with a plurality of temperature sensors associated with components of the heat pump 104, the outdoor unit 106, and/or the ground heat exchanger 108. Such temperature sensors may include a heat pump outlet 128 temperature sensor that measures the temperature of the fluid circulated by the heat pump 104 at the heat pump outlet 128, a heat pump inlet 130 temperature sensor that measures the temperature of the fluid circulated by the heat pump 104 at the heat pump inlet 130, an outdoor heat exchanger 124 inlet 132 temperature sensor that measures the temperature of the fluid circulated by the heat pump 104 at the inlet 132 of the outdoor heat exchanger 124, an outdoor heat exchanger 124 outlet 134 temperature sensor that measures the temperature of the fluid circulated by the heat pump 104 at the outlet 134 of the outdoor heat exchanger 124, a ground heat exchanger 108 inlet 136 temperature sensor that measures the temperature of the fluid circulated by the heat pump 104 at the inlet 136 of the ground heat exchanger 108, and a ground heat exchanger 108 outlet 138 temperature sensor that measures the temperature of the fluid circulated by the heat pump 104 at the outlet 138 of the ground heat exchanger 108. Additionally, the system controller 102 may also be configured to monitor and/or communicate with a temperature sensor that measures the ambient outdoor air 201 temperature and/or a temperature sensor that measures the ground 202 temperature. It will further be appreciated that in some embodiments, the temperatures described herein as monitored by the system controller 102 may be monitored by and communicated to the system controller 102 by one of the aforementioned heat pump 104 controller and/or the outdoor unit 106 controller.

The system controller 102 may generally comprise a touchscreen interface for displaying information related to the operation of the hybrid heat pump system 100 and/or for receiving user inputs of a temperature set point, a humidity set point, schedules, and/or any other user defined inputs that affect control and/or operation of the hybrid heat pump system 100 and/or its components. However, the system controller 102 may further be operable to display information and/or receive user inputs tangentially and/or unrelated to operation of the hybrid heat pump system 100. In some embodiments, however, the system controller 102 may not comprise a display and may derive all information from inputs from remote sensors and remote configuration tools.

In operation, system controller 102 is configured to control the components of the hybrid heat pump system 100 to selectively circulate a fluid (i.e. water, water/glycol mixture, and/or any other heat transfer medium) through a selectively altered fluid flow path between the heat pump 104, the outdoor heat exchanger 124 of the outdoor unit 106, and the ground heat exchanger 108 in response to inputs and/or feedback from the various disclosed temperature sensors. The system controller 102 may continuously monitor the temperature sensors and/or temperatures disclosed herein, or, may alternatively receive feedback from the temperature sensors at predetermined intervals. As will be discussed, the system controller 102 may control and/or alter the fluid flow path of the hybrid heat pump system 100 by opening and/or closing any configuration of the plurality of valves 110, 112, 114, 116, 118, 120 in response to the temperatures associated with the hybrid heat pump system 100, the heating and/or cooling demand in the structure 200, the ambient outdoor air 201 temperature, the ground 202 temperature, and/or any combination and/or comparison thereof. In some embodiments, the selection of valves 110, 112, 114, 116, 118, 120 to open and/or close may be based on maximizing a temperature gradient between the fluid circulated by the heat pump 104 and an associated heat transfer medium (i.e. the ambient outdoor air 201 and/or the ground 202). As such, the system controller 102 may be operated to selectively remove the outdoor unit 106 and/or the ground heat exchanger 108 from the fluid flow path of the hybrid heat pump system 100 and/or selectively change the flow of direction and/or sequence through the outdoor unit 106 and the ground heat exchanger 108.

Referring now to FIG. 2, a schematic diagram of the hybrid heat pump system 100 of FIG. 1 configured in a first mode (ground mode) of operation is shown according to an embodiment of the disclosure. Generally, in the ground mode of operation, the hybrid heat pump system 100 may be configured to only exchange heat with the ground 202. Accordingly, the outdoor heat exchanger 124 of the outdoor unit 106 may be removed from the fluid flow path by closing the first valve 110, the second valve 112, the third valve 114, and the fourth valve 116. Thus, the fifth valve 118 and the sixth valve 120 remain open, such that the fluid circulated by the heat pump 104 may exit the heat pump 104 at the heat pump outlet 128, pass through the fifth valve 118, enter the ground heat exchanger 108 through the inlet 136 of the ground heat exchanger 108, pass through the ground loops 126, and exit the ground heat exchanger 108 at the outlet 138 of the ground heat exchanger 108 before passing through the sixth valve 120 and returning to the heat pump 104 through the heat pump inlet 130.

In operation, when the system controller 102 receives a demand for heating or cooling, the system controller 102 may determine the temperatures of the ambient outdoor air 201 and the ground 202. The system controller 102 may compare the temperatures of the ambient outdoor air 201 and the ground 202. When the system controller 102 receives a demand for heating, the hybrid heat pump system 100 will be configured in the ground mode when the temperature of the ground 202 is greater than the temperature of the ambient outdoor air 201 to pull heat from the ground 202. Conversely, when the system controller 102 receives a demand for cooling, the hybrid heat pump system 100 will be configured in the ground mode when the temperature of the ground 202 is less than the temperature of the ambient outdoor air 201 to discharge heat to the ground 202. Accordingly, the ground mode may be employed by the system controller 102 when the ground 202 temperature is greater than the ambient outdoor air 201 temperature during operation of the hybrid heat pump system 100 in a heating mode, and when the ground 202 temperature is less than the ambient outdoor air 201 temperature during operation of the hybrid heat pump system 100 in a cooling mode.

Referring now to FIG. 3, a schematic diagram of the hybrid heat pump system of FIG. 1 configured in a second mode (air mode) of operation is shown according to an embodiment of the disclosure. Generally, in the air mode of operation, the hybrid heat pump system 100 may be configured to only exchange heat with the ambient outdoor air 201 when conditions are opposite of those associated with the ground mode of FIG. 2. Accordingly, the ground heat exchanger 108 may be removed from the fluid flow path by closing the first valve 110, the fourth valve 116, and the fifth valve 118. Thus, the second valve 112, the third valve 114, and the sixth valve 120 remain open, such that the fluid circulated by the heat pump 104 may exit the heat pump 104 at the heat pump outlet 128, pass through the second valve 112, enter the outdoor heat exchanger 124 of the outdoor unit 106 through the inlet 132 of the outdoor heat exchanger 124, pass through the outdoor heat exchanger 124, and exit the outdoor heat exchanger 124 at the outlet 134 of the outdoor heat exchanger 124 before passing through the third valve 114 and the sixth valve 120, sequentially and returning to the heat pump 104 through the heat pump inlet 130.

In operation, when the system controller 102 receives a demand for heating or cooling, the system controller 102 may determine the temperatures of the ambient outdoor air 201 and the ground 202. The system controller 102 may compare the temperatures of the ambient outdoor air 201 and the ground 202. When the system controller 102 receives a demand for heating, the hybrid heat pump system 100 will be configured in the air mode when the temperature of the ground 202 is less than the temperature of the ambient outdoor air 201 to pull heat from the ambient outdoor air 201. Conversely, when the system controller 102 receives a demand for cooling, the hybrid heat pump system 100 will be configured in the air mode when the temperature of the ground 202 is greater than the temperature of the ambient outdoor air 201 to discharge heat to the ambient outdoor air 201. Accordingly, the air mode may be employed by the system controller 102 when the ground 202 temperature is less than the ambient outdoor air 201 temperature during operation of the hybrid heat pump system 100 in a heating mode, and when the ground 202 temperature is greater than the ambient outdoor air 201 temperature during operation of the hybrid heat pump system 100 in a cooling mode.

Referring now to FIG. 4, a schematic diagram of the hybrid heat pump system 100 of FIG. 1 configured in a third mode (air-ground mode) of operation is shown according to an embodiment of the disclosure. Generally, in the air-ground mode of operation, the hybrid heat pump system 100 may be configured to exchange heat with both the ambient outdoor air 201 and the ground 202. Accordingly, the first valve 110, the third valve 114, and the fifth valve 118 may be closed. Thus, the second valve 112, the fourth valve 116, and the sixth valve 120 remain open, such that the fluid circulated by the heat pump 104 may exit the heat pump 104 at the heat pump outlet 128, pass through the second valve 112, enter the outdoor heat exchanger 124 of the outdoor unit 106 through the inlet 132 of the outdoor heat exchanger 124, pass through the outdoor heat exchanger 124, exit the outdoor heat exchanger 124 at the outlet 134 of the outdoor heat exchanger 124, pass through the fourth valve 116, enter the ground heat exchanger 108 through the inlet 136 of the ground heat exchanger 108, pass through the ground loops 126, and exit the ground heat exchanger 108 through the outlet 138 of the ground heat exchanger 108 before passing through the sixth valve 120 and returning to the heat pump 104 through the heat pump inlet 130.

In operation, when the system controller 102 receives a demand for heating or cooling, the system controller 102 may determine the temperatures of the ambient outdoor air 201 and the ground 202. The system controller 102 may also determine the temperature of the fluid circulated by the heat pump 104 at the outlet 134 of the outdoor heat exchanger 124 and/or the temperature of the fluid circulated by the heat pump 104 at the inlet 136 of the ground heat exchanger 108. The system controller 102 may compare the temperatures of the ambient outdoor air 201 and the ground 202. The system controller 102 may also compare the temperature of the fluid circulated by the heat pump 104 at the inlet 136 of the ground heat exchanger 108 with the temperature of the ground 202. When the system controller 102 receives a demand for heating, the hybrid heat pump system 100 will be configured in the air-ground mode when the temperature of the ground 202 is less than the temperature of the ambient outdoor air 201 and when the temperature of the fluid circulated by the heat pump 104 at the inlet 136 of the ground heat exchanger 108 is less than the temperature of the ground 202 such that heat from the ambient outdoor air 201 and the ground 202 may be transferred to the fluid circulated by the heat pump 104. Conversely, when the system controller 102 receives a demand for cooling, the hybrid heat pump system 100 will be configured in the air-ground mode when the temperature of the ground 202 is greater than the temperature of the ambient outdoor air 201 and when the temperature of the fluid circulated by the heat pump 104 at the inlet 136 of the ground heat exchanger 108 is greater than the temperature of the ground 202 such that heat from the fluid circulated by the heat pump 104 may be discharged into the ambient outdoor air 201 and the ground 202. Accordingly, the air-ground mode may be employed by the system controller 102 when the ground 202 temperature is less than the ambient outdoor air 201 temperature and when the temperature of the fluid circulated by the heat pump 104 at the inlet 136 of the ground heat exchanger 108 is less than the temperature of the ground 201 during operation of the hybrid heat pump system 100 in a heating mode, and when the ground 202 temperature is greater than the ambient outdoor air 201 temperature and when the temperature of the fluid circulated by the heat pump 104 at the inlet 136 of the ground heat exchanger 108 is greater than the temperature of the ground 202 during operation of the hybrid heat pump system 100 in a cooling mode.

Referring now to FIG. 5, a schematic diagram of the hybrid heat pump system 100 of FIG. 1 configured in a fourth mode (ground-air mode) of operation is shown according to an embodiment of the disclosure. Generally, in the ground-air mode of operation, the hybrid heat pump system 100 may be configured to exchange heat with both the ambient outdoor air 201 and the ground 202 when conditions are opposite of those associated with the air-ground mode of FIG. 4. Accordingly, operation of the valves associated with the ground-air mode of FIG. 4 may be reversed. The second valve 112, the fourth valve 116, and the sixth valve 120 may be closed, while the first valve 110, the third valve 114, and the fifth valve 118 remain open. Additionally, the direction of fluid flow through the outdoor heat exchanger 124 may also be reversed with respect to the air-ground mode of FIG. 4 such that the fluid circulated by the heat pump 104 may enter the outdoor heat exchanger 124 through the outlet 134 and exit the outdoor heat exchanger 124 through the inlet 132. Further, the sequence of fluid flow through the outdoor heat exchanger 124 and the ground heat exchanger 108 may also be reversed with respect to the air-ground mode of FIG. 4, such that the fluid circulated by the heat pump 104 passes through the ground heat exchanger 108 prior to entering the outdoor heat exchanger 124. Thus, the fluid circulated by the heat pump 104 may exit the heat pump 104 at the heat pump outlet 128, pass through the fifth valve 118, enter the ground heat exchanger 108 through the inlet 136 of the ground heat exchanger 108, pass through the ground loops 126, exit the ground heat exchanger 108 through the outlet 138 of the ground heat exchanger 108, pass through the third valve 114, enter the outdoor heat exchanger 124 through the outlet 134 of the outdoor heat exchanger 124, pass through the outdoor heat exchanger 124, and exit the outdoor heat exchanger 124 through the inlet 132 of the outdoor heat exchanger 124 before passing through the first valve 110 and returning to the heat pump 104 through the heat pump inlet 130.

In operation, when the system controller 102 receives a demand for heating or cooling, the system controller 102 may determine the temperatures of the ambient outdoor air 201 and the ground 202. The system controller 102 may also determine the temperature of the fluid circulated by the heat pump 104 at the outlet 138 of the ground heat exchanger 108 and/or the temperature of the fluid circulated by the heat pump 104 at the inlet 134 of the outdoor heat exchanger 106. The system controller 102 may compare the temperatures of the ambient outdoor air 201 and the ground 202. The system controller 102 may also compare the temperature of the fluid circulated by the heat pump 104 at the inlet 134 of the outdoor heat exchanger 124 with the temperature of the ambient air 201. When the system controller 102 receives a demand for heating, the hybrid heat pump system 100 will be configured in the ground-air mode when the temperature of the ground 202 is greater than the temperature of the ambient outdoor air 201 and when the temperature of the fluid circulated by the heat pump 104 at the inlet 134 of the outdoor heat exchanger 124 is less than the temperature of the ambient outdoor air 201 such that heat from the ambient outdoor air 201 and the ground 202 may be transferred to the fluid circulated by the heat pump 104. Conversely, when the system controller 102 receives a demand for cooling, the hybrid heat pump system 100 will be configured in the ground-air mode when the temperature of the ground 202 is less than the temperature of the ambient outdoor air 201 and when the temperature of the fluid circulated by the heat pump 104 at the inlet 134 of the outdoor heat exchanger 124 is greater than the temperature of the ambient outdoor air 201 such that heat from the fluid circulated by the heat pump 104 may be discharged into the ambient outdoor air 201 and the ground 202. Accordingly, the ground-air mode may be employed by the system controller 102 when the ground 202 temperature is greater than the ambient outdoor air 201 temperature and when the temperature of the fluid circulated by the heat pump 104 at the inlet 134 of the outdoor heat exchanger 124 is less than the temperature of the ambient outdoor air 201 during operation of the hybrid heat pump system 100 in a heating mode, and when the ground 202 temperature is less than the ambient outdoor air 201 temperature and when the temperature of the fluid circulated by the heat pump 104 at the inlet 134 of the outdoor heat exchanger 106 is greater than the temperature of the ambient outdoor air 201 during operation of the hybrid heat pump system 100 in a cooling mode.

It will be appreciated that when the system controller 102 configures the hybrid heat pump system 100 in any of the ground mode, the air mode, the air-ground mode, or the ground-air mode, the system controller 102 may adjust and/or control the plurality of valves 110, 112, 114, 116, 118, 120 to open and/or close the valves depending on the demand for heating or cooling within the structure 200 and/or the comparison of the various temperatures associated with the hybrid heat pump system 100. Additionally, in some embodiments, the system controller 102 may selectively communicate with other controllers, such as a heat pump 104 controller, an outdoor unit 106 controller, and/or other components of the hybrid heat pump system 100 to operate the hybrid heat pump system 100 in a heating mode and/or a cooling mode, and/or to provide commands to the heat pump 104 controller and/or the outdoor unit 106 controller to adjust and/or control the plurality of valves 110, 112, 114, 116, 118, 120 to open and/or close the valves to selectively alter the fluid flow path between the heat pump 104, the outdoor heat exchanger 124 of the outdoor unit 106, and the ground heat exchanger 108. Furthermore, this disclosure contemplates that other strategies may be incorporated into the hybrid heat pump system 100 and/or the system controller 102 where the ambient outdoor air 201 may be used to “precondition” the fluid circulated by the heat pump 104 before it enters the ground heat exchanger 108, so that the ground 202 may be heated and/or cooled in anticipation of future weather and/or thermal conditions.

Referring now to FIG. 6, a flowchart of a method 300 of operating the hybrid heat pump system 100 of FIGS. 1-5 is shown according to an embodiment of the disclosure. The method 300 may begin at block 302 by providing a hybrid heat pump system 100 comprising an outdoor unit 106 and a ground heat exchanger 108 connected to a heat pump 104 via a plurality of valves 110, 112, 114, 116, 118, 120. The method 300 may continue at block 304 by receiving a demand for heating or cooling. This may be accomplished by the system controller 102 receiving an input from a user or a temperature of a zone associated with a structure, such as structure 200, exceeding a predefined temperature threshold. The method 300 may continue at block 306 by measuring temperatures associated with the hybrid heat pump system 100. In some embodiments, the temperatures may comprise a temperature of the ground 202 and a temperature of the ambient outdoor air 201. In other embodiments, the temperatures may also comprise a temperature of a fluid circulated by the heat pump 104 at an inlet 136 of the ground heat exchanger 108. The method 300 may continue at block 308 by selectively configuring a plurality of valves to control a fluid flow path of a fluid circulated by the heat pump 104 in response to a comparison of the temperatures. In some embodiments, this may be accomplished by the system controller 102 configuring the hybrid heat pump system 100 in one of the ground mode, the air mode, the air-ground mode, and the ground-air mode. The method 300 may continue at block 310 by flowing a fluid through at least one of an outdoor heat exchanger 124 of the outdoor unit 106 to exchange heat with ambient outdoor air 201 and the ground heat exchanger 108 to exchange heat with the ground 202.

At least one embodiment is disclosed and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, R_(l), and an upper limit, R_(u), is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=R_(l)+k*(R_(u)−R_(l)), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . , 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Unless otherwise stated, the term “about” shall mean plus or minus 10 percent of the subsequent value. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention. 

What is claimed is:
 1. A hybrid heat pump system, comprising: a heat pump; an outdoor heat exchanger; a ground heat exchanger; and a fluid flow path including a plurality of valves selectively configurable to circulate fluid between the heat pump, the outdoor heat exchanger, and the ground heat exchanger.
 2. The hybrid heat pump system of claim 1, further comprising an outdoor unit comprising a fan and the outdoor heat exchanger.
 3. The hybrid heat pump system of claim 1, wherein the plurality of valves are selectively configurable between: a first valve configuration wherein the fluid flow path circulates fluid between the heat pump, the outdoor heat exchanger, and the ground heat exchanger; a second valve configuration wherein the fluid flow path circulates fluid between the heat pump and the ground heat exchanger; and a third valve configuration wherein the fluid flow path circulates fluid between the heat pump and the outdoor heat exchanger.
 4. The hybrid heat pump system of claim 3, further comprising one or more temperature sensors, and wherein selection between the first, second, and third valve configuration is based on a temperature sensed by the one or more temperature sensors.
 5. The hybrid heat pump system of claim 1, further comprising a controller in communication with the plurality of valves to promote selection between: a first valve configuration wherein the fluid flow path circulates fluid between the heat pump, the outdoor heat exchanger, and the ground heat exchanger; a second valve configuration wherein the fluid flow path circulates fluid between the heat pump and the ground heat exchanger; and a third valve configuration wherein the fluid flow path circulates fluid between the heat pump and the outdoor heat exchanger.
 6. The hybrid heat pump system of claim 5, further comprising one or more temperature sensors in communication with the controller, and wherein the controller selects between the first, second, and third valve configuration based on a temperature sensed by the one or more temperature sensors.
 7. A hybrid heat pump system, comprising: a heat pump; an outdoor heat exchanger; a ground heat exchanger; and a fluid flow path including a plurality of valves selectively configurable: in a first mode to circulate fluid between the heat pump and the ground heat exchanger, in a second mode to circulate fluid between the heat pump and the outdoor heat exchanger, in a third mode to circulate fluid from the heat pump to the outdoor heat exchanger and then circulate the fluid from the outdoor heat exchanger to the ground heat exchanger, and in a fourth mode to circulate fluid from the heat pump to the ground heat exchanger and then circulate the fluid from the ground heat exchanger to enter the outdoor heat exchanger.
 8. The hybrid heat pump system of claim 7, further comprising one or more temperature sensors in communication with a controller, and wherein the controller is configured to select between the first, second, third, and fourth modes based on a temperature sensed by the one or more temperature sensors.
 9. The hybrid heat pump system of claim 7, further comprising one or more temperature sensors, and wherein selection between the first, second, third, and fourth modes is based on a temperature sensed by the one or more temperature sensors.
 10. The hybrid heat pump system of claim 7, further comprising an outdoor unit comprising a fan and the outdoor heat exchanger.
 11. A method of operating hybrid heat pump system, comprising: circulating fluid between a heat pump and a ground heat exchanger in a first mode; circulating fluid between the heat pump and an outdoor heat exchanger in a second mode; circulating fluid from the heat pump to the outdoor heat exchanger and then circulating the fluid from the outdoor heat exchanger to the ground heat exchanger in a third mode; and circulating fluid from the heat pump to the ground heat exchanger and then circulating the fluid from the ground heat exchanger to enter the outdoor heat exchanger in a fourth mode.
 12. The method of claim 11, wherein the fluid is circulated through a fluid flow path via a plurality of valves that are selectively configurable.
 13. The method of claim 11, further comprising one or more temperature sensors in communication with a controller, and wherein the controller is configured to select between the first, second, third, and fourth modes based on a temperature sensed by the one or more temperature sensors.
 14. The method of claim 11, further comprising one or more temperature sensors, and wherein selection between the first, second, third, and fourth modes is based on a temperature sensed by the one or more temperature sensors. 